Chapter 46. PL/Python — Python Procedural Language

Table of Contents

46.1. Python 2 vs. Python 3
46.2. PL/Python Functions
46.3. Data Values
46.3.1. Data Type Mapping
46.3.2. Null, None
46.3.3. Arrays, Lists
46.3.4. Composite Types
46.3.5. Set-Returning Functions
46.4. Sharing Data
46.5. Anonymous Code Blocks
46.6. Trigger Functions
46.7. Database Access
46.7.1. Database Access Functions
46.7.2. Trapping Errors
46.8. Explicit Subtransactions
46.8.1. Subtransaction Context Managers
46.8.2. Older Python Versions
46.9. Transaction Management
46.10. Utility Functions
46.11. Environment Variables

The PL/Python procedural language allows PostgreSQL functions and procedures to be written in the Python language.

To install PL/Python in a particular database, use CREATE EXTENSION plpythonu (but see also Section 46.1).


If a language is installed into template1, all subsequently created databases will have the language installed automatically.

PL/Python is only available as an untrusted language, meaning it does not offer any way of restricting what users can do in it and is therefore named plpythonu. A trusted variant plpython might become available in the future if a secure execution mechanism is developed in Python. The writer of a function in untrusted PL/Python must take care that the function cannot be used to do anything unwanted, since it will be able to do anything that could be done by a user logged in as the database administrator. Only superusers can create functions in untrusted languages such as plpythonu.


Users of source packages must specially enable the build of PL/Python during the installation process. (Refer to the installation instructions for more information.) Users of binary packages might find PL/Python in a separate subpackage.